Assessing alternate furrow strategies for potato at the Cherfech irrigation district of Tunisia

Irrigated agriculture faces intense competition for water in Mediterranean environments. In this paper, alternate furrow irrigation (AFI) was explored for a potato crop in the conditions of the Cherfech irrigation district, located in the Medjerda project of northern Tunisia. A field experiment was performed involving seven furrow irrigations in three irrigation treatments: alternate furrow irrigation, fixed furrow irrigation (FFI), and conventional furrow irrigation (CFI). Crop yield and water productivity were determined in all treatments. The experiment involved detailed irrigation evaluation and soil water measurements in the first three irrigation events. Soil infiltration (estimated with a surface irrigation model) was larger for CFI than for AFI or FFI. This finding was confirmed by the average irrigation depths, which amounted to 65, 60 and 91 mm for the AFI, FFI and CFI treatments, respectively. Application and irrigation efficiency were higher in FFI than in AFI, while in CFI efficiency was much lower. Water productivity (expressed as the ratio of yield to irrigation water) amounted to 8.0, 8.7 and 5.9 kg m(-3) for the AFI, FFI and CFI treatments, respectively. Soil water-yield simulations indicated that alternate furrow irrigation did not result in reduced yield, neither for the experimental treatment nor for deficit irrigation scenarios characterised by six or five irrigation events. Alternate furrow irrigation stands as a simple management technique resulting in relevant water conservation in the local conditions. (C) 2010 IAgrE. Published by Elsevier Ltd. All rights reserved.